Provided herein are pro-VP antagonists, such as antibodies and antigen-binding portions thereof specific for pro-VP, for identifying and targeting expressing cancer cells. Applicants additionally provide methods of using said compositions, for example to image cancer cells in vivo and in biological samples. The compositions may also be used for treating patients suffering from a provasopressin-expressing cancer. Provasopressin-expressing cancers include neuroendocrine cancer, pancreatic cancer, and prostate cancer.

Provided herein are antagonists or binding agents of an abnormal vasopressin receptor V_(2 )(e.g., AbnV_(2)), such as antibodies and antigen-binding portions thereof specific for the receptor, for identifying and targeting cancer cells expressing such abnormal vasopressin receptor V_(2). Additionally provided are methods of using said antagonists or binding agents, for example, to image cancer cells or in biological samples, or diagnose cancers, both in vivo and in vitro. The antagonists or binding agents may also be used for treating patients suffering from a cancer expressing the abnormal vasopressin receptor V_(2), such as small cell lung cancer (SCLC), breast cancer, or ovarian cancer.

DESCRIPTION (provided by applicant): There is currently no effective treatment for recurrent small-cell lung cancer (rSCLC). The objective of this project is to utilize a monoclonal antibody, Abner, to develop new, rational, and successful treatment of rSCLC. The hypothesis being tested is that an abnormal vasopressin type 2 receptor (AbnV2R) present on these tumors will provide a sensitive, tumor-specific, and reliable target for the effective treatment by Abner antibodies. The data from the studies of Phase 1 of the project clearly show that treatment of variant SCLC tumor xenografts, with native and 90Yttrium-labelled mouse Abner significantly slows growth, but this growth is completely impaired when antibody treatment follows cyclophosphamide. Our data indicate AbnV2R expression is a feature common to all, or most, SCLC and that AbnV2R is a surface protein. Phase 2 is directed at advancing treatment of rSCLC with Abner by developing a human chimeric form (cAbner) of the mouse monoclonal antibody, and thena humanized form (hAbner) as potential clinical candidates. The ability of cAbner and hAbner to target and prevent growth of human variant SCLC xenografts in mice will then be tested. Phase 2 goals are directed towards (i) generating a chimeric form (cAbner) of mouse Abner with the constant regions of human IgG1; (ii) establishing that the targeting, recognition, and treatment profiles of mAbner are retained by cAbner; (iii) modeling a humanized form (hAbner) of Abner from the cAbner with genetically grafting CDRs from the VH and VL regions of mMAG-1 into the DNA framework of a human antibody; (iv) establishing that the targeting, recognition, and treatment profiles of mAbner are retained by hAbner. These investigations will employ, RT-PCR, ligation, and cloning, DNA recombinance, DNA sequencing, immunohistochemistry, antibody modification, Northern and Western analysis with densiometric quantitation, ELISA, RIA, tumor-directed targeting, whole-body scintigraphy for 99mTechnetium, cytofluorographic and radiometric quantitation, confocal microscopy, radioligand binding, flow cytometry, and cell and tumor growth assessments with mechanism analysis in vitro and for nu/nu mice. A successful end-point of our Phase 2 studies would be the generation of cAbner and/orhAbner forms of our antibody that show a similar binding affinity as mAbner, recognize all or most recurrent (and primary) cancers, do not react with normal tissues, and can reduce the size of tumors, and/or prevent their growth in vivo. The proposed research is expected to rapidly lead to new and successful therapeutic approaches for managing recurrent small-cell lung cancer. PUBLIC HEALTH RELEVANCE: This project will introduce a new targeted therapeutic approach for the treatment of recurrent small-cell lung cancer, a disease that is refractory to all current treatments. This refractoriness means lt 10% expected 5 year survival rate for patients representing gt 40,000 new cases of SCLC that arise in the USA each year. Our targeted approach is directed at a newly discovered abnormal receptor which seems to be a tumor-specific surface marker of recurrent small-cell lung cancer. Targeting will employ an available monoclonal antibody to treat this deadly disease. This antibody recognizes a unique extracellular portion of the marker. Currently patients with recurrent SCLC usually succumb to the disease in 3 to 6 months. The proposed research is expected to lead to new successful therapies for managing recurrent SCLC, thereby leading to a higher long-term survival rate for these patients.

DESCRIPTION (provided by applicant): There is currently no effective treatment for recurrent small-cell lung cancer (rSCLC). The objective of this project is to utilize a monoclonal antibody, MAG-1, to develop new, rational, and successful treatment of rSCLC. The hypothesis being tested is that a cancer -specific provasopressin antigen, called GRSA, present at the surface of these tumors will provide a sensitive, tumor-specific, and reliable target for the effective treatment by MAG-1 antibodies in combination with cyclophosphamide. Our preliminary data clearly show that treatment of variant SCLC tumor xenografts, with native and 90Yttrium-labelled mouse MAG-1 significantly slows growth, but this growth is almost completely impaired when antibody treatment follows cyclophosphamide. GRSA expression is a feature common to all, or most, SCLC and is absent from normal tissues. Phase 1 of this study is directed at advancing treatment of rSCLC using both mouse MAG-1 and already generated human chimeric MAG-1 a

DESCRIPTION (provided by applicant): The objective of this Phase 1 project is to improve an effective treatment of recurrent small-cell lung cancer (rSCLC) by targeting a tumor-specific abnormal receptor, AbnV2 that is a surface-marker of the disease. Currently, there is no effective treatment for rSCLC. Our data show expression of this abnormal vasopressin V2 receptor (AbnV2 ) is a common feature of recurrent as well as primary cancers, and can be targeted by polyclonal and monoclonal antibodies recognizing unique features in a C-terminal extracellular domain. They are absent from normal tissues. Polyclonal Abs can inhibit in vitro the growth of cancer cells derived from recurrent as well as primary tumors. Expression of such receptors therefore not only raises the possibility to develop new and successful therapies for this disease, but also methods for detecting residual tumor and monitoring treatment. Such therapies should have particular relevance to recurrent disease. The hypothesis being tested is that the AbnV2 receptor will provide a sensitive and reliable target for effective treatment of recurrent rSCLC, and that monoclonal antibodies can serve as effective therapeutic targeting agents. Phase 1 goals are directed towards:(i) performing a 'proof ofprinciple' evaluation of the effectiveness of unmodified and/or 90Y-labeled anti-AbnV2 monoAb to destroy/prevent growth of variant (and recurrent disease derived) NCI H82 and classical (and primary tumor-derived) NCI H345 SCLC cells grown in athymic mice;(ii) establishing the distribution and abundance in SCLC tumors of AbnV2 receptor protein and its unique expression by these tumors, and;(iii) determining the ability of anti-AbnV2 monoAb to inhibit the growth of SCLC cells in culture, and exploring mechanisms through which growth inhibition is accomplished. Treatment with forms of anti-AbnV2 monoAb will be compared with ubiquitous immunoglobulin (MOPC21). These investigations are designed to employ, tumor targeting in a mouse model, cytofluorographic and radiometric quantitation, antibody modification, tumor growth assessments, assessment of apoptotic and necrotic changes, IHC, ELISA, RIA, flow cytometry, RT-PCR, DNA sequencing, and Western analysis with densiometric quantitation. The approach employed is considered innovative because it represents the first treatment of form of recurrent SCLC cancer with an unmodified tumor-specific antibody. It is also provides the possibility that treatment progress can be monitored by use of radio-labeled fragments of the same antibody. A successful end-point of our Phase 1 studies would be the clear determination that unmodified, and/or 90Yttrium-labeled, anti-AbnV2 antibody can destroy or significantly curtail the growth of SCLC tumors in vivo, and that AbnV2 is a marker for gt50% of SCLC tumors. Phase 2 would involve the preclinical testing of chimeric and humanized forms of anti-AbnV2 on SCLC. The proposed research is expected to rapidly lead to new and successful therapeutic approaches for managing recurrent small-cell lung cancer. rSCLC resists all current efforts at treatment. PUBLIC HEALTH RELEVANCE: This project will introduce a new targeted therapeutic approach for the treatment of recurrent small-cell lung cancer, a disease that is refractory to all current treatments. This refractoriness means lt 10% expected 5 year survival rate for patients representing gt 40,000 new cases of SCLC that arise in the USA each year. Our targeted approach is directed at a newly discovered abnormal receptor which seems to be a tumor-specific surface marker of recurrent small-cell lung cancer. Targeting will employ an available monoclonal antibody to treat this deadly disease. This antibody recognizes a unique extracellular portion of the marker. Currently patients with recurrent SCLC usually succumb to the disease in 3 to 6 months. The proposed research is expected to lead to new successful therapies for managing recurrent SCLC, thereby leading to a higher long- term survival rate for these patients.

Provided herein are pro-VP antagonists, such as antibodies and antigen-binding portions thereof specific for pro-VP, for identifying and targeting expressing cancer cells. Applicants additionally provide methods of using said compositions, for example to image cancer cells in vivo and in biological samples. The compositions may also be used for treating patients suffering from a provasopressin-expressing cancer. Provasopressin-expressing cancers include neuroendocrine cancer, pancreatic cancer, and prostate cancer.

Provided herein are antagonists or binding agents of an abnormal vasopressin receptor V_(2 )(e.g., AbnV_(2)), such as antibodies and antigen-binding portions thereof specific for the receptor, for identifying and targeting cancer cells expressing such abnormal vasopressin receptor V_(2). Additionally provided are methods of using said antagonists or binding agents, for example, to image cancer cells or in biological samples, or diagnose cancers, both in vivo and in vitro. The antagonists or binding agents may also be used for treating patients suffering from a cancer expressing the abnormal vasopressin receptor V_(2), such as small cell lung cancer (SCLC), breast cancer, or ovarian cancer.